100^th Day of School- Apples for the Teacher- This has some really good resources and ideas

http://www.apples4theteacher.com/holidays/100th-day-of-school/

100^th Day of School from WebTech

http://webtech.kennesaw.edu/jcheek3/100thday.htm

Math worksheets for 100th Day of School by ABC Teach

http://www.abcteach.com/directory/basics/math/100th_day_of_school/

100^th day of School by the Teacher’s Corner

http://www.theteacherscorner.net/seasonal/100days/index.htm

100^th Day of School by GP Schools

Includes a section of online activities, printable pages, lesson activities and poetry and songs

http://www.gpschools.org/ci/ce/elem/holidays/100days.htm

100^th Day of School Suggested Classroom Activities

http://www.siec.k12.in.us/~west/proj/100th/act.htm

100^th Day by A to Z Teachers

http://atozteacherstuff.com/Themes/100th_Day/

100^th Day of School by Enchanted Learning

http://www.enchantedlearning.com/themes/hundred.shtml